Liquid fuel injection pumping apparatus

ABSTRACT

A fuel pumping apparatus comprises an injection pump defining a pump chamber, and also a spill port extending from the pump chamber, the pump includes a spill valve which is rotatable in synchronism with the injection pump to control flow of fuel through the spill port. The axial setting of the spill valve is determined by weights which move the spill valve in opposition to the action of a spring and the angular setting is determined by further weights which move a hollow cylindrical member 34 axially against the action of a spring. The cylindrical member has helical spline engagement with a pulley.

United States Patent 1191 Glikin et al.

[ 1 Dec. 31, 1974 v 1 LIQUID FUEL INJECTION PUMPING APPARATUS [75] Inventors: Paul Edgar Glikin; Zdzislav Stanislav Miracki, both of London; Ronald Phillips, Northolt, all of England [73] Assignee: Simms Group Research &

Development Limited, London, England 1221 Filed: June 21,1973 21 Appl.No.:372,494

[30] 1 Foreign Application Priority Data July 13, 1972 Great Britain 32776/72 52 U.S. (21.....1 123/139 AP 51 1111.01. F02d 1/12 [58] Field of Search... 123/139 AP, 140 R [56] References Cited UNITED STATES PATENTS 2,729,167

3/1950 Links 123/139 2,764,964 10/1956 Meyer 123/ 139 3,185,141 5/1965 Miracki et a1. 123/140 R 3,398,729 8/1968 Maddalozz0.. 123/139 3,648,673 3/1972 Knape 123/139 R Primary Examiner-Manuel A. Antonakas Assistant Examiner-J. W. Cranson Attorney, Agent, or Firm-Holman & Stern 157] ABSTRACT A fuel pumping apparatus comprises an injection pump defining a pump chamber, and also a spill port extending from the pump chamber, the pump includes a spill valve which is rotatable'in synchronism with the injection pumpto control flow of fuel through the spill port. The axial setting of the spill valve is determined by weights which move the spill valve in opposition to the action-of a spring'and the angular setting is determined by further weights which move a hollow cylindrical member 34 axially against the action of a spring. The cylindrical member has helical spline engagement with a pulley.

6 Claims, 4 Drawing Figures PATENTEDnEwmm v SHEETEOF 3 LIQUID FUEL INJECTION PUMPING APPARATUS This invention relates to liquid fuel injection pumping apparatus for supplying fuel to internal'combustion engines and has for its object to provide such an apparatus in a simple and convenient form.

A liquid fuel injection pumping apparatus in accordance with the invention comprises in combination an injection pumpdefining a pumping chamber, an outlet extending from the pumping chamber and which in use, is connected to an engine cylinder, a spill port extending from the pumping chamber, a spill valve rotatable in synchronism with the injection pump for controlling the fiow of fuel through the spill port during a pumping stroke of the injection pump, the axial setting of said spill valve determining the quantity of fuel supplied through the outlet and the angular setting of the spill valve relative to the injection pump serving to alter the timing of injection of fuel through said outlet to the engine, first centrifugal means for moving the spill valve axially'in a direction to reduce the amount of fuel supplied to the engine, said first centrifugal means effecting movement of the spill valve against the action of first resilient means the force exerted by whichcan be determined by the operator of the engine, and second centrifugal means operable to effect angular movement of the spill valve relative to a driving member for the spill valve. 7

One example of a liquid fuel injection pumping apparatus in accordance with the invention will now be described with reference to the accompanying drawings in which:

FIG. 1 is a sectional side elevation of part of the apparatus, v

FIG. 2 is a section on the line 8-8 of FIG. 1,

FIG. 3 is a section on the line E-E of P16. 1, and

FIG. 4 is a perspective view of a portion of the apparatus seen in! H6. 1. a Referring to the drawings there is provided a body portion which as shown particularlyin FIG. 2, is formed in two parts 11 and 12. The lower part 12 carries a rotary cam shaft 13 which is driven in timed relationship with an engine with which.the apparatus is associated. The camshaft carries a plurality of cams 14 which as the cam shaft rotates, impart inward movement to pumping plungers 15 which are reciprocably located within bores 16 formed in the upper portion 11 of the body part. Each plunger 15 is provided with a spring 17 to urge the plunger outwardly and the end of the plunger is contacted by a tappet 18 which is slidably accommodated within a respective bore located in the lower portion 12 of the body part. The tappet carries a roller 19 for co-operation with the periphery of the cam. Moreover, the tappet is restrained against angular movement by means ofa suitably positioned screw having an end portion which locates within a groove formed in the tappet.

As will be seen from P10. 2 the bores 16 are inclined and in addition are. staggered along the length of the body part and intermediate the bores is located a cen-' tral drilling 20 which accommodates a cylindrical member 21 having grooves formed on its periphery at intervals along its length and registering approximately with the bores 16. v

Each bore is provided with an outlet 22 for connection respectively with an injection nozzle of the associated engine and the outlets 22 may be controlled by delivery valves not shown. In addition each bore communicates with a spill port 23 which opens into the aforesaid drilling 20 moreover, in the same plane as the spill port 23 there is provided a plurality of spill passages 24 respectively these being located at right angles to the ports 23. The spill passages open into the drilling 20 and at their other ends open into a chamber 25 extending the length of the body of the apparatus.

With reference now to FIGS. 1 and 3, there is secured to the body part 10 a housing 27 into which the cam shaft 13 extends. Mounted on the cam shaft is a toothed wheel 28 about which is engaged a toothed belt 29. The belt also extends around a pulley 30 which is journalled in the housing'27. The pulley 30 is of hollow cylindrical form and mounted on the end of the pulley remote from the body part 107is an outwardly extending fiangeportion 31. The flange portion 31 mounts a plurality of lugs 32 each of which mounts a centrifugally operable weight 33. Four such weights are provided the weights being divided into-pairs for the prupose to be explained.

Mounted within the pulley 30 and having helical spline connection therewith is a hollow cylindrical member 34 which forms an abutment for a coiled c'om-.

pression spring '35. The other abutment for the compression spring 35 is constituted by housing 36 which .is mounted on the flange 31. The axial setting of the member 34 is determined by a pair of the weights 33 which for this purpose are provided with arms 37 (FIG.

3),the arms engaging'with a step defined upon the periphery ofthe member 34. Extending through the member 34 is a rod 38 which is in driving engagement with the member 21 whereby axial and angular movement of the rod 38 will impart axial and angular movement to the member 21. In addition the rod 38 at onepoint along its length is provided with a transversely extending plate 39 which locates in a pair of axially extending slots formed in the member 34. By this arrangement angular movement of the member 34 will be transferred to the rod 38' but relative axial movement can. take place therebetween. The plate 39 is engaged by legs 40 carried by the other of the pair of weights 33 and axial movement of the rod 38'under the action of the weights 33 is resisted by means of a leaf spring 41 engaged by the end of the rod 38. The leaf spring is pivotally mounted within the housing 27 and operator adjustable means 42 is provided to enable the force exerted spring 41 upon the rod 38, to be adjusted.

In operation, as the cam shaft 13 is rotated rotary movement will be imparted to the. pulley 30 and by way of the helical spline connection, to the member 34. R0- tary motion of the member 34 will be transmitted to the rod 38 by means of the tongue 39 and the rotary motion of the rod 38 will be transmitted to the member 21.

- As the speed of rotation of the cam shaft increases, the

as compared with the cam shaft 13.

by the Connected to the cam shaft 13 is the rotor of the vane type feed pump 43 and this supplies fuel by way ofa passage 44 formed in the housing 27, to the gallery 25. A cylindrical connector piece not shown is provided intermediate the housing and the lower portion 12 of the body part of the pump. In addition, and as shown in FIG. 3, a combined accumulator and relief valve 45 is provided to control the outlet pressure of the feed pump. It will be noted from FIG. 2 of the drawings that the space above the tappet 18 communicates with the aforesaid gallery and therefore the tappets are in part actuated by hydraulic pressure. It will be noted that the downward or outward motion of one of the tappets occurs at the same time as the upward or inward motion of another tappet. In this manner the volume of fuel in the gallery 25 remains substantially unchanged.

Turning now to FIG. 4 there is shown a perspective view ofa portion of the member 21 and this view shows two sets of grooves 46, each set of grooves constitutes a rotary spill valve. The direction of rotation of the member is indicated by the arrow and it will be seen that the trailing edge 47 of the groove is disposed substantially parallel to the axis of rotation of the member. The leading edge 48 of the groove is obliquely disposed relative to the axis of rotation of the member and the minor are intermediate these edges constitutes a land 49. The major and remaining portion of arc is substantially unobstructed and constitutes a groove. Minor lands 50 are however provided, (only one of which is seen), to strengthen the member 21. The circumferential width of the minor lands 50 is such that they do not obstruct the port 23 or the passage 24.

The member 21 rotates at twice the speed of the cam shaft 13 and it is so positioned relative to the cam shaft that during the inward or upward movement of the plunger associated with a particular set of grooves, the land 49 obstructs the spill port 23 so that fuel displaced by the plunger flows through the outlet 22 to the associated injection nozzle. Since the edge 47 of the land 49 extends parallel to the axis of rotation of the member 21, what ever the axial position of the member the spill port 23 will always be covered at the same time so that injection of fuel to the associated engine will always start at the same instant. Since the edge 48 of the land 49is obliquely disposed the termination of injection of fuel and therefore the quantity of fuel which is supplied to the engine, will depend upon the axial position of the member 21 and as has already been explained the axial position of the member 21 depends upon the axial position of the rod 38 and the setting of weights 33 which operate upon the tongue 39. If relative angular movement takes place between the member 34 and the pulley 30 a variation in the start of injection of fuel to the engine will occur. At the end of the injection of fuel to the engine when the spill port 23 is uncovered the fuel which is displaced by the plunger flows by way of the groove to the gallery by way of the passage 24 and during outward movement of the plunger fuel flows through the passage 24, the groove on the member 21 and the spill port 23 into the bore 16 so that the latter is completely filled with fuel. It will be noted that as the member 21 is moved towards the right an increase of fuel delivered to the engine will occur.

In order to control the maximum quantity of fuel which can be supplied to the engine a maximum fuel stop 51 is provided and this co-operates with a flange 52 formed on the end of the rod 38 against which the spring 41 bears. The setting of the stop 51 which is in fact a lever can be determined by adjustment of a screw 53. In addition means not shown is provided to cooperate with the flange 52 to effect movement of the member 21 to its extreme left hand position. In this position the circumferential width of the land 49 is less than that of the spill port 23 so that no fuel will be delivered to the engine.

As shown in the drawings the connection between the pulley 30 and the wheel 28 which is mounted on the can shaft 13 of the apparatus is by means of a toothed belt 29. In an alternative arrangement a gear connection can be provided between the cam shaft and the pulley 30 and if desired the gear connection may be arranged to constitute the fuel feed pump 43.

We claim:

1. A liquid fuel injection pumping apparatus comprising in combination, an injection pump adapted to be driven in timed relationship with an associated engine,

said injection pump defining a pumping chamber, an outlet from the pumping chamber and which in use is connected to a nozzle mounted in an engine cylinder, a spill port extending from the pumping chamber, a spill valve rotatable in synchronism with the injection pump for controlling the flow of-fuel through the spill port during a pumping stroke of the injection pump, the axial setting of said spill valve determining the quantity of fuel supplied through the outlet and the angular setting of the spill valve relative to the injection pump serving to alter the timing of injection of fuel through said outlet to the engine, a pulley rotatable in synchronism with the injection pump, means restraining the pulley against axial movement, a flange mounted on said pulley and rotatable therewith, a first centrifugal weight pivotally mounted on said flange, a hollow cylindrical member located within a bore formed in the pulley, a helical spline connection between the pulley and said hollow cylindrical member, a rod extending within said hollow cylindrical member, said rod being coupled to said spill valve, means connecting said rod to said hollow cylindrical member. whereby relative .axial movement ofthe rod and cylindrical member can occur,a leverintegral with said first weight, said lever extending through an aperture in said hollow cylindrical member and engaging said rod for moving with increasing engine speed the spill valve axially in a direction to reduce the amount of fuel supplied to the engine, first resilient means acting on the rod in opposition to the force exerted by said first centrifugal weight operator adjustable means for varying the force exerted by the first resilient means, and a second centrifugal weight carried by said flange, a lever connected to said second weight, said lever engaging said hollow cylindrical member whereby with varying engine speed the axial position of the hollow cylindrical member will vary to effect angular movement of the spill valve relative to said pulley.

2. An apparatus according to claim 1 in which said spill valve defines a land of varying circumferential width throughout its axial length.

3. An apparatus according to claim 2 in which said means connecting said rod to said hollow cylindrical member comprises a lateral plate located within an axial slot formed in the wall of said cylindrical member, said plate being secured to said rod.

said coiled compression spring.

6. An apparatus according to claim 5 in which said rod extends through said housing and a leaf spring Y forming said first resilient means, said leaf spring engaging with the end of said rod, the force exerted by said leaf spring opposing mevement of the rod by said first centrifugal weight. 

1. A liquid fuel injection pumping apparatus comprising in combination, an injection pump adapted to be driven in timed relationship with an associated engine, said injection pump defining a pumping chamber, an outlet from the pumping chamber and which in use is connected to a nozzle mounted in an engine cylinder, a spill port extending from the pumping chamber, a spill valve rotatable in synchronism with the injection pump for controlling the flow of fuel through the spill port during a pumping stroke of the injection pump, the axial setting of said spill valve determining the quantity of fuel supplied through the outlet and the angular setting of the spill valve relative to the injection pump serving to alter the timing of injection of fuel through said outlet to the engine, a pulley rotatable in synchronism with the injection pump, means restraining the pulley against axial movement, a flange mounted on said pulley and rotatable therewith, a first centrifugal weight pivotally mounted on said flange, a hollow cylindrical member located within a bore formed in the pulley, a helical spline connection between the pulley and said hollow cylindrical member, a rod extending within said hollow cylindrical member, said rod being coupled to said spill valve, means connecting said rod to said hollow cylindrical member whereby relative axial movement of the rod and cylindrical member can occur, a lever integral with said first weight, said lever extending through an aperture in said hollow cylindrical member and engaging said rod for moving with increasing engine speed the spill valve axially in a direction to reduce the amount of fuel supplied to the engine, first resilient means acting on the rod in opposition to the force exerted by said first centrifugal weight operator adjustable means for varying the force exerted by the first resilient means, and a second centrifugal weight carried by said flange, a lever connected to said second weight, said lever engaging said hollow cylindrical member whereby with varying engine speed the axial position of the hollow cylindrical member will vary to effect angular movement of the spill valve relative to said pulley.
 2. An apparatus according to claim 1 in which said spill valve defines a land of varying circumferential width throughout its axial length.
 3. An apparatus according to claim 2 in which said means connecting said rod to said hollow cylindrical member comprises a lateral plate located within an axial slot formed in the wall of said cylindrical member, said plate being secured to said rod.
 4. An apparatus according to claim 3 in which said hollow cylindrical member forms an abutment for a coiled compression spring said member being axially movable by said second centrifugal weight against the action of said spring.
 5. An apparatus according to claim 4 including a housing mounted on said flange, said housing surrounding said weights and forming a further abutment for said coiled compression spring.
 6. An apparatus according to claim 5 in which said rod extends through said housing and a leaf spring forming said first resilient means, said leaf spring engaging with the end of said rod, the force exerted by said leaf spring opposing mevement of the rod by said first centrifugal weight. 